Recording tape cartridge

ABSTRACT

A recording tape cartridge in which melting, abrasion or the like does not occur at a portion of abutting of a brake member with a release member, or with a release portion of a drive device, during rotation of a reel. In this recording tape cartridge, a magnetic tape is wound onto the reel at a reel hub inside a case. A brake member is non-rotatably provided inside the case. The reel is rotation-locked when the brake member is disposed at a rotation-locking position, at which the brake member engages with an engaging protrusion of a bottom portion. A release pad is disposed between the bottom portion and the brake member and abuts against both thereof. When the release pad holds the brake member at a rotation-enabling position, the reel is rotatable. When the reel rotates with the release pad, a metal-formed rubbing protrusion portion of the brake member, which is a convex spherical surface with a radius of at least 3 mm, and a resin-formed rubbing protrusion of the release pad, which is a flat surface, rub against one another.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under 35USC 119 from JapanesePatent Application No. 2002-366602, the disclosure of which isincorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a recording tape cartridge whichrotatably accommodates a reel onto which recording tape, such as amagnetic tape or the like, is wound.

[0004] 2. Description of the Related Art

[0005] Recording tapes such as magnetic tapes and the like are used asexternal recording media for computers and the like. “One-reel”recording tape cartridges, which rotatably accommodate a single reelonto which a recording tape is wound, take up little space when storedand can record large amounts of information, and are employed as suchrecording tapes.

[0006] Such a recording tape cartridge is equipped with a brakestructure such that the reel does not rotate inside the case at times ofnon-use (see, for example, the specification of Japanese Patent No.3,187,022). A recording tape cartridge equipped with this brakestructure is now described with reference to FIGS. 13 and 14.

[0007] In a recording tape cartridge 200 shown in FIG. 13, a single reel204 is accommodated in a case 202. The case 202 is provided with a gearaperture 206 and a rotation-limiting rib 208. The gear aperture 206 isformed at a central portion of a floor plate 202A of the case 202. Therotation-limiting rib 208 protrudes downward from a ceiling plate 202Bof the case 202.

[0008] The reel 204 is provided with a reel hub 210, which is formed ina circular tube shape with a base, around an outer peripheral portion ofwhich recording tape is wound. At a lower face of abase portion 210A ofthe reel hub 210, a reel gear 214 is formed in an annular shape. Thereel gear 214 is meshable with a driving gear 212A, which is formed at arotation shaft 212 of a drive device. Insertion through-holes 216, whichpenetrate through the base portion 210A, are provided at a plurality oflocations on a circular periphery, at the portion at which the reel gear214 is formed. The insertion through-holes 216 are equidistant. Adiameter of each insertion through-holes 216 is set to be larger than agear pitch of the reel gear 214, and teeth of the reel gear 214 are notprovided in a vicinity of each insertion through-hole 216.

[0009] At an upper face of the base portion 210A of the reel hub 210,engaging protrusions 218 are provided standing from (portions of) aplurality of locations along the predetermined circular periphery,between the insertion through-holes 216. Gear teeth 218A are formed atupper end portions of the engaging protrusions 218.

[0010] A disc-like brake member 220 is insertedly provided inside thereel hub 210. At a lower face of the brake member 220, an annular brakegear 220A is provided. The brake gear 220A is capable of meshing withthe gear teeth 218A. A projection 222 is provided standing from an upperface of the brake member 220. The projection 222 is provided with aninsertion groove 222A, into which the rotation-limiting rib 208 of thecase 202 is inserted. When the rotation-limiting rib 208 enters thisinsertion groove 222A, the brake member 220 is rendered incapable ofrotating relative to the case 202. Moreover, the brake member 220 isrendered movable only in a vertical direction, being guided by therotation-limiting rib 208.

[0011] A compression coil spring 224 is disposed between the ceilingplate 202B of the case 202 and the brake member 220. Usually, the brakemember 220 is urged downward by urging force of the compression coilspring 224, whereby the brake gear 220A is meshed with the gear teeth218A. Thus, the brake member 220 is ordinarily in a rotation-lockedstate in which rotation of the reel 204 relative to the case 202 isblocked. Moreover, the reel 204 is pressed against the floor plate 202Aof the case 202 by this urging force, and the reel gear 214 is exposedthrough the gear aperture 206.

[0012] Further, a release member 226 is disposed between the baseportion 210A of the reel hub 210 and the brake member 220, so as to abutagainst the base portion 210A and the brake member 220. The releasemember 226 is formed in a plate form which does not interfere with theengaging protrusions 218, and is provided with leg portions 226A, whichare respectively inserted into the insertion through-holes 216.

[0013] Thus, when the driving gear 212A is operated to mesh with thereel gear 214, as shown in FIG. 14, the leg portions 226A are pushed bythe driving gear 212A, against the urging force of the compression coilspring 224, and the release member 226 is pushed upward. The releasemember 226 moves away from the base portion 210A and pushes the brakemember 220 upward. Thus, meshing between the brake gear 220A and thegear teeth 218A is released. At this time, the reel 204 also risesrelative to the floor plate 202A, and the reel 204 becomes rotatableinside the case 202.

[0014] The release member 226 has structure such that, in a state inwhich meshing of the driving gear 212A with the reel gear 214 ismaintained, the leg portions 226A of the release member 226 are incontact with the driving gear 212A, and thus the release member 226holds the brake member 220 at the release position described above.

[0015] Hence, the reel 204, whose reel gear 214 meshes with the drivinggear 212A of the rotation shaft 212 when the rotation shaft 212 rotates,is a structure which rotates in the case 202. At this time, the releasemember 226 whose leg portions 226A are inserted into the insertionthrough-holes 216 of the reel 204 rotates integrally with the reel 204,and an axial center portion of the reel 204 rubs against (i.e.,slidingly contacts) an axial center portion of the brake member 220.

[0016] Then, when the state of meshing of the driving gear 212A with thereel gear 214 is released, the brake member 220 is moved downward by theurging force of the compression coil spring 224, the brake gear 220Ameshes with the gear teeth 218A, and the reel 204 is pushed against thefloor plate 202A. As a result, the structure returns to therotation-locked state in which rotation of the reel 204 relative to thecase 202 is blocked.

[0017] The brake member 220 and release member 226 described above areboth formed by resin-molding, such that complex forms can be producedwith ease. In order to reduce rubbing resistance between the brakemember 220 and the release member 226 when the reel 204 rotates, aportion of the brake member 220 that abuts (rubs) against the releasemember 226, which is an axial center portion of the brake member 220, isformed with a protrusion portion 220B, which is formed substantially ina spherical surface form. Thus, the brake member 220 is substantially inpoint contact with the axial center portion of the release member 226.Conversely, a portion of the release member 226 that abuts against theprotrusion portion 220B of the brake member 220 is formed as aprotrusion portion 226B, whose upper end is a flat surface. Thus, thisstructure has low susceptibility to occurrences of off-centering of therelatively rotating brake member 220 and release member 226.

[0018] Further, in order to effect a function of alignment between thebrake member 220 and the release member 226, in addition to preventingthis off-centering, a structure is known in which one of these abuttingportions is formed as a convex surface and the other is structured as aconcave surface with a greater diameter than the convex surface (see,for example, Japanese Patent Application (JP-A) No. 2000-331454).

[0019] Anyway, in recent years, increases in recording density of therecording tape cartridge have been demanded. In response to thesedemands, for example, reducing thickness of the recording tape andlengthening an amount of the recording tape that is wound onto the reelhas been considered. Further, in accordance with increases in speeds ofwriting information onto the recording tape and reading information thathas been recorded onto the recording tape, increasing a drawing-outspeed (feeding speed) of the recording tape has been considered.Accordingly, for the recording tape cartridge 200, measures to deal witha lengthening of a continuous rotation time of the reel 204 and anincrease in rotation speed of the reel 204 have been demanded.

[0020] However, at the recording tape cartridge 200, during rotation ofthe reel 204, the protrusion portion 220B of the brake member 220 andthe protrusion portion 226B of the release member 226, which arerespectively resin members, rub against one another. Therefore, if therotation speed of the reel 204 becomes greater (for example, a feedingspeed of the recording tape of 6 m/s or more) and the duration of therotation becomes longer, heat is generated by rubbing resistance, andthus there is a problem in that the protrusion portion 220B and theprotrusion portion 226B will melt. This problem similarly arises in thestructure of JP-A No. 2000-331454.

[0021] Further, although this is not shown in the drawings, a structureis also known in which the release member 226 is not provided (forexample, JP-A No. 63-251983). The protrusion portion 220B of the brakemember 220 is directly pushed by a release portion. The release portionis protrudingly provided at an axial center portion of the rotationshaft 212 and advances in through a through-hole which penetratesthrough the base portion 210A of the reel hub 210. Thus, the brakemember 220 is pushed up, and the rotation-locked state of the reel 204is released. In this structure too, the protrusion portion 220B and thedrive device side release portion rub against one another duringrotation of the reel 204, and are formed of resin materials. Therefore,under the usage conditions described above, there is a risk that theprotrusion portion 220B or the release portion may begin to melt. Notethat, similarly to the protrusion portion 226B, a surface of the releaseportion of the drive device that rubs against the protrusion portion220B is a flat surface.

[0022] Accordingly, in order to suppress this generation of heat, astructure (for example, JP-A No. 2002-197833) has been considered inwhich a portion corresponding to the protrusion portion 226B of therelease member 226 is structured of a metallic material. Thus, rubbingresistance between the metallic material and the protrusion portion220B, which is a resin material, is reduced. In this structure, thegeneration of heat in accordance with rubbing resistance between theprotrusion portion 220B and the protrusion portion 226B is suppressed,and melting of the resin material protrusion portion 220B is prevented.

[0023] However, in the structure disclosed in JP-A No. 2002-197833,under conditions in which the rotation speed of the reel 204 has beenincreased and the rotation duration has been lengthened as describedearlier, there is a problem in that the spherical surface-formprotrusion portion 220B, which is the resin side, is abraded or worndown (crushed), and height thereof becomes lower. JP-A No. 2002-197833further discloses a structure in which a metallic sphere is fitted in atthe brake member 220 to form the surface abutting against the releasemember 226. However, for such a case, diameter of the metallic sphere,the form of the abutting surface of the release member 226 which is theopposite member, and the like are not described at all. That is, in thestructures of JP-A No. 2002-197833, melting, abrasion or the like doesnot occur at the resin side abutting portion under predeterminedconditions (i.e., conditions such that a magnetic tape which has beendrawn out 10 metres from the case is wound back onto the reel in thecase by an operation of 25,000 revolutions), but abrasion or wearing ofthe resin side abutting portion under conditions in which the rotationspeed of the reel 204 has been increased and the rotation duration hasbeen lengthened, corresponding to conditions of use which are expectedhereafter, has not been considered at all, and such abrasion or the likecannot be prevented.

[0024] Thus, if melting of the protrusion portion 220B and theprotrusion portion 226B or abrasion of the protrusion portion 220B orthe like occurs as described above, the brake member 220, which is urgedby the compression coil spring 224, moves downward and an amount ofinsertion of the rotation-limiting rib 208 into the insertion groove222A of the brake member 220 is reduced. At the projection 222 and therotation-limiting rib 208 of the case 202, which are channel walls ofthe insertion groove 222A, draft angling is provided for die release ata time of resin-molding. Therefore, when the above-mentioned insertionamount decreases, a gap between an inner face of the projection 222 andthe rotation-limiting rib 208 becomes larger, and this is a cause oflooseness of the brake member 220 and the generation of noise duringrotation of the reel 204. Further, in the recording tape cartridge 200in which the protrusion portion 220B abuts against the protrusionportion 226B (i.e., a structure of Japanese Patent No. 3,187,022, JP-ANo. 2000-331454 or JP-A No. 2002-197833), a reduction in the insertionamount causes looseness of the brake member 220 at times of non-use.

SUMMARY OF THE INVENTION

[0025] In light of the circumstances described above, an object of thepresent invention is to provide a recording tape cartridge in whichmelting, abrasion or the like does not occur at a portion of a releasemember, or of a release portion of a drive device, which portion abutsagainst a brake member during rotation of a reel.

[0026] In order to achieve the object described above, according to afirst aspect of the present invention, a tape cartridge which isinsertable at a tape drive which includes a rotating member and carriesout at least one of reading and writing of data is provided, which tapecartridge includes: a reel inside the tape cartridge, the rotatingmember of the tape drive being engageable with the reel at a time ofinsertion of the tape cartridge, for transmitting rotary driving forceto the reel; a brake member which is reciprocally movable between alocking position for prohibiting rotation of the reel and an unlockingposition for enabling rotation of the reel; and a release pad which iscapable of engaging with the rotating member and abutting against thebrake member for the reciprocal movement of the brake member. One ofmutually abutting portions of the brake member and the release padincludes a metallic surface which includes one of a flat surface formand a spherical form with a spherical radius of at least 3 mm, and theother of the mutually abutting portions includes a resin surface whichincludes one of a flat surface form and a curvedly recessed surfaceform.

[0027] According to another aspect of the present invention, a tapecartridge which is insertable at a tape drive which includes a rotatingmember and carries out at least one of reading and writing of data isprovided, which tape cartridge includes: a reel inside the tapecartridge, the rotating member of the tape drive being engageable withthe reel at a time of insertion of the tape cartridge, for transmittingrotary driving force to the reel; a brake member which is reciprocallymovable between a locking position for prohibiting rotation of the reeland an unlocking position for enabling rotation of the reel; and anabutting portion provided at the brake member, the abutting portionbeing fabricated of metal and including an abutting surface which iscapable of abutting against the rotating member for the reciprocalmovement of the brake member at the time of insertion of the tapecartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a perspective view showing overall structure of arecording tape cartridge relating to a first embodiment of the presentinvention.

[0029]FIG. 2 is an exploded perspective view of the recording tapecartridge relating to the first embodiment of the present invention.

[0030]FIG. 3 is a bottom view of an upper case which structures therecording tape cartridge relating to the first embodiment of the presentinvention.

[0031]FIG. 4 is a plan view of a lower case which structures therecording tape cartridge relating to the first embodiment of the presentinvention.

[0032]FIG. 5A is a plan view showing an opening process of an opening ofthe recording tape cartridge relating to the first embodiment of thepresent invention, viewed with the upper case removed, which shows aninitial state of engagement of an engaging protrusion of a drive devicewith an operation projection of a door.

[0033]FIG. 5B is a plan view showing the same opening process, whichshows a state during opening of the opening.

[0034]FIG. 5C is a plan view showing the same opening process, whichshows a state of completed opening of the opening.

[0035]FIG. 6 is an exploded perspective view, viewed from below, showinga reel and a brake structure which structure the recording tapecartridge relating to the first embodiment of the present invention.

[0036]FIG. 7 is a sectional view showing a rotation-locked state of thereel of the recording tape cartridge relating to the first embodiment ofthe present invention.

[0037]FIG. 8 is a sectional view showing a rotation-enabled state of thereel of the recording tape cartridge relating to the first embodiment ofthe present invention.

[0038]FIG. 9 is a partial enlarged sectional view showing an abuttingportion of a brake member and a release pad which structure therecording tape cartridge relating to the first embodiment of the presentinvention.

[0039]FIG. 10A corresponds to FIG. 9, showing a variant example of theabutting portion of the brake member and release pad which structure therecording tape cartridge relating to the first embodiment of the presentinvention, and is a sectional view of a first variant example.

[0040]FIG. 10B corresponds to FIG. 9, showing another variant example ofthe abutting portion, and is a sectional view of a second variantexample.

[0041]FIG. 10C corresponds to FIG. 9, showing another variant example ofthe abutting portion, and is a sectional view of a third variantexample.

[0042]FIG. 10D corresponds to FIG. 9, showing another variant example ofthe abutting portion, and is a sectional view of a fourth variantexample.

[0043]FIG. 11 is a sectional view showing a rotation-locked state of areel of a recording tape cartridge relating to a second embodiment ofthe present invention.

[0044]FIG. 12 is a sectional view showing a rotation-enabled state ofthe reel of the recording tape cartridge relating to the secondembodiment of the present invention.

[0045]FIG. 13 is a sectional view showing a rotation-locked state of areel of a conventional recording tape cartridge.

[0046]FIG. 14 is a sectional view showing a rotation-enabled state ofthe reel of the conventional recording tape cartridge.

DETAILED DESCRIPTION OF THE INVENTION

[0047] A recording tape cartridge 10 relating to a first embodiment ofthe present invention will be explained on the basis of FIGS. 1 to 9.Firstly, general overall structure of the recording tape cartridge 10,and structure of an opening and a door, will be explained. Then, a reel14 and a brake structure which prevents rotation of the reel 14 at timesof non-use, which are principal elements of the present invention, willbe explained. For the sake of convenience of explanation, a loadingdirection of the recording tape cartridge 10 into a drive device, whichis shown by arrow A, is referred to as a forward direction (a frontside) of the recording tape cartridge 10, and the direction of an arrowB, which intersects arrow A, is a rightward direction.

[0048] Overall Structure of Recording Tape Cartridge

[0049]FIG. 1 shows a perspective view of overall structure of therecording tape cartridge 10. FIG. 2 shows a schematic explodedperspective view of the recording tape cartridge 10.

[0050] As shown in these drawings, the recording tape cartridge 10 isstructured to rotatably accommodate the single reel 14 in a case 12. Thecase 12 is substantially rectangular in plan view. A magnetic tape T iswound onto the reel 14. The magnetic tape T serves as a recording tapewhich is an information recording/replaying medium. Structure of thisreel will be described later.

[0051] The case 12 is structured by matching up and joining twoperipheral walls 16A and 18A of an upper case 16 and a lower case 18 toone another. A front-right corner portion of each of the upper case 16and the lower case 18, which is a single corner portion at a front endside in the direction of loading into the drive device, is cut away. Anaccommodation space for the reel 14, onto which the magnetic tape T iswound, is provided inside the case 12. Hence, the cut away cornerportions of the peripheral walls 16A and 18A of the upper case 16 andthe lower case 18 serve as an opening 20 for drawing out the magnetictape T. Details of the opening 20 and a door 50, which opens and closesthe opening 20, will be described later.

[0052] A leader pin 22 is connected at a free end of the magnetic tape Twhich is to be drawn out through the opening 20. The leader pin 22 iscaught up (engaged) by drawing-out means of the drive device, andsubjected to a drawing-out operation. At each of two end portions of theleader pin 22, which protrude beyond width direction end portions of themagnetic tape T, an annular groove 22A is formed. These annular grooves22A are caught on to by hooks or the like of the drawing-out means.Consequently, in this structure, the hooks or the like do not contactand damage the magnetic tape T when the magnetic tape T is drawn out.

[0053] At an inner side of the opening 20 of the case 12, a pair ofupper and lower pin stands 24 are provided for positioning and retainingthe leader pin 22 in the case 12. The pin stands 24 have semi-tubularforms which open toward the direction of arrow B, and both the endportions of the leader pin 22 are held at recess portions 24A of the pinstands 24 in a state in which the leader pin 22 is standing thereat. Thepin stands 24 join with ribs 44, which are described below.

[0054] A leaf spring 25 is fixedly disposed in a vicinity of the pinstands 24. The leaf spring 25 engages with upper and lower end portionsof the leader pin 22, and holds the leader pin 22 at the pin stands 24.The leaf spring 25 has a structure in which an arm portion 25Aresiliently deforms as appropriate to allow movement of the leader pin22 when the leader pin 22 is removed or inserted at the pin stands 24.

[0055] A gear aperture 26 is formed at a central portion of the lowercase 18. The gear aperture 26 serves as an ‘aperture’ of the presentinvention for exposing a reel gear 66 (which is described later) of thereel 14 to the outside. The reel gear 66 meshes with a driving gear of adrive device and drives the reel 14 to rotate inside the case 12. Thereel 14 is held by free play-restricting walls 28 so as not to rattleabout. These free play-restricting walls 28 are projectingly provided atinterior surfaces of the upper case 16 and the lower case 18, to serveas interior walls which are disposed along portions of a circular pathwhich is coaxial with the gear aperture 26. Further, at the 18, at edgeportions of the gear aperture 26, an annular rib 26A is providedprotruding toward the inside of the case 12. The annular rib 26A is usedfor positioning of the reel 14.

[0056] A hollow portion 28A is provided continuously with an end portionof the free play-restricting walls 28 in a vicinity of the opening 20. Ahole for regulation of position is formed at an interior portion of thehollow portion 28A. In addition, a hollow portion 28B is standinglyprovided in a space which is sandwiched between the freeplay-restricting walls 28 and a front-left corner portion of the case12. Another hole for regulation of position, which is a long hole, isformed in the hollow portion 28B. The hollow portions 28A and 28B aredisposed co-linearly along the direction of arrow B. Except for an endportion at which the hollow portion 28A is continuously provided, endportions of each of the free play-restricting walls 28 are provided tobe continuous with the peripheral wall 16A or the peripheral wall 18A ofthe case 12. Thus, an outer side of the free play-restricting walls 28is set apart from the space for disposing the reel 14.

[0057] A memory board M is disposed at a rear-right portion of the lowercase 18. The memory board M stores various kinds of information for eachindividual recording tape cartridge 10. A portion of a rear wall 18C,which structures the peripheral wall 18A, is inclined to the extent of apredetermined angle and the memory board M is disposed to be inclined atthe predetermined angle. Hence, the memory board M can be detected at adrive device, which reads the memory board M from a lower face side, andat a library apparatus, which reads the memory board M from a rear faceside.

[0058] Structure of Opening and of Case at Opening Vicinity

[0059] As shown in FIG. 3, which is a bottom view of the upper case 16,and FIG. 4, which is a plan view of the lower case 18, respective pairsof upper and lower screw bosses 32 and screw bosses 36 are provided atfront and rear edge portions of the opening 20. Together with otherscrew bosses, which are not shown, the screw bosses 32 and 36 are forscrew-fixing to join the upper case 16 and the lower case 18 together.

[0060] The screw bosses 32, which are disposed at the front edge portionof the opening 20, are provided continuously with both a right endportion of a front wall 12A of the case 12 (a portion of the peripheralwalls 16A and 18A whose outer surface faces in the direction of arrow A)and a pair of short upper and lower anti-dust walls 30, which isinflected along an opening face of the opening 20 from the right endportion of the front wall 12A. A recess portion 30A is formed betweenthe screw bosses 32 and the anti-dust walls 30. A distal end portion ofthe door 50, which is described later, enters into the recess portion30A.

[0061] At the screw bosses 36, which are located at the rear edgeportion of the opening 20, a front end portion of a right wall 12B ofthe case 12 (a right side wall portion of the peripheral walls 16A and18A, which runs along the direction of arrow A) is provided continuouslywith both an inflected wall 38, which is inflected to run substantiallyalong the opening face of the opening 20, and a front end portion of apair of upper and lower circular arc walls 34, which pair is provided atan inner side of the right wall 12B. The upper and lower circular arcwalls 34 are respectively formed in circular arc shapes substantiallycorresponding to an outer peripheral face of the later-described door 50(and to a movement path of the door 50) in plan view. The circular arcwalls 34 respectively protrude rearward to the extent of a predeterminedlength from the screw bosses 36. A rear end portion of the circular arcwalls 34 is joined with the right wall 12B (the peripheral wall 16A andthe peripheral wall 18A) via a short joining wall 34A.

[0062] A slit 40 is provided in the right wall 12B of the case 12. Theslit 40 has a predetermined length and serves as a window portion whichcommunicates between the interior and exterior of the case 12. The slit40 is for exposing an operation projection 52 of the later-describeddoor 50. The slit 40 is formed by cutting away a lower portion of theperipheral wall 16A that structures the right wall 12B. A lower portionof the inflected wall 38 of the upper case 16 is also cut away. Thus,the slit 40 also opens forward.

[0063] Guide grooves 42 for guiding the door 50 are formed in the uppercase 16 and lower case 18 structuring the case 12. Groove walls of theguide grooves 42 are structured by ribs 44, which are provided standingfrom a ceiling plate 16B of the upper case 16 and a floor plate 18B ofthe lower case 18, by the right wall 12B (the peripheral wall 16A andthe peripheral wall 18A), and by the free play-restricting walls 28.Thus, the guide grooves 42 are formed without reducing thickness of theceiling plate 16B and the floor plate 18B. The ribs 44 are providedcontinuously with the pin stands 24.

[0064] Each of the guide grooves 42 is formed in a circular arc shapealong a predetermined circular circumference. The recess portion 30Aserves as an end portion of the guide grooves 42, and the guide grooves42 reach therefrom to a rear-right corner portion of the case 12. Thepredetermined circular circumference is determined so as to pass(thread) between the right wall 12B and the free play-restricting walls28 at an outer side of the screw bosses 32 and at an inner side of thescrew bosses 36. A center point of the predetermined circularcircumference (a center of rotation of the later-described door 50) isspecified such that a position (coordinate) thereof in the left-rightdirection is at an outer side relative to a left end of the case 12 anda position (coordinate) thereof in the front-rear directionsubstantially corresponds to a center of rotation of the reel 14 (whichis at a center point of the free play-restricting walls 28).

[0065] At a portion of the guide channels 42 that is located at theopening 20, the ribs 44 are cut away rightward of the pin stands 24.Thus, the guide channels 42 are communicated with the recess portions24A, and are communicated with a spring groove 45, at which the armportion 25A of the leaf spring 25 is disposed. At this cut-away portionof the guide grooves 42, A tapering opening 20A, which guides the leaderpin 22 into the case 12, is communicated with the recess portions 24A ofthe pin stands 24. Ribs 46, which are formed along each of a rear edgeof the tapering opening 20A, a front end of the screw bosses 36, and theopening face of the opening 20 are provided continuously with the ribs44B. Thus, strength of surroundings of the opening 20 of the case 12 ispreserved or improved in spite of the ribs 44 having been cut away.

[0066] Rear ends of the ribs 44, which structure rear half portions ofthe guide grooves 42, curve back on themselves in substantial U shapes.The rib 44 of the upper case 16 is formed to extend further to the rearthan the rib 44 of the lower case 18. The purpose of this is to preventinterference between the door 50 and the memory board M disposed at theright wall 12B side of the rear wall 18C, which rear wall 18C (of theperipheral wall 18A) of the lower case 18 is a surface inclined at apredetermined angle.

[0067] A pair of upper and lower spring-engaging pins 55 are provided ata length direction central portion of the rear half portion of the ribs44, at an inner side portion thereof. Each spring-engaging pin 55 isprovided continuously with the free play-restricting walls 28. The lowercase 18 side spring-engaging pin 55 is formed to be longer, and aportion thereof which protrudes further upward than the correspondingfree play-restricting wall 28 is a structure at which a one end sideannular portion 56A of a coil spring 56, which is described later, hookson. Then, the upper case 16 side spring-engaging pin 55, which isshorter, matches up with the lower case 18 side spring-engaging pin 55,and disengagement of the coil spring 56 is blocked.

[0068] In a state in which the peripheral walls 16A and 18A of the uppercase 16 and lower case 18 described above are matched together,unillustrated screws are screwed into the screw bosses 32, the screwbosses 36 and other screw bosses from the lower side, and the screwbosses are fixed (joined) to structure the case 12. Here, because theopening 20 is formed by cutting away the front-right corner portion ofthe rectangular case 12, the opening face of the opening 20 faces in thedirection of arrow A and in the direction of arrow B. Consequently, thedrawing-out means of a drive device can access and chuck the leader pin22 from the direction of arrow A, from the direction of arrow B, or froma direction between the directions of arrow A and arrow B. As a result,an area in which the pin stands 24 that hold the leader pin 22 can bedisposed is large, and a range from which drawing-out means of drivedevices can chuck the leader pin 22 is wide. Accordingly, a position atwhich the pin stands 24 are disposed can be specified to meetspecifications of drive devices that carry out chucking from direction Aand drive devices that carry out chucking from direction B. Thus, adegree of freedom of design of the drive devices is broadened.

[0069] Structure of Door

[0070] The opening 20 described above is opened and closed by the door50, which serves as a covering member. The door 50 is curved in a platethickness direction thereof and is formed in a circular arc form whosecurvature substantially coincides with the curvature of the guidegrooves 42 (the predetermined circular circumference) in plan view. Aportion of the door 50 at a front half portion thereof (at least aportion which closes off the opening 20) serves as a closing portion50A, which is formed with a plate breadth (height) set to besubstantially the same as an opening height of the opening 20. A portionof the door 50 that is rearward relative to the closing portion 50Aserves as a driven portion 50B, with a plate breadth which is set to beslightly smaller.

[0071] The plate length of the door 50 (the curved length dimension) isdetermined such that, in a state in which the opening 20 is closed, arear end portion of the driven portion 50B is disposed inside therear-right corner portion of the case 12 (see FIG. 5A). A lower-rearportion of the driven portion 50B is cut away at an angle in order toavoid the memory board M which is disposed at the inclined surface ofthe rear wall 18C.

[0072] Thus, the door 50 is a structure which closes the opening 20 in astate in which a distal end portion of the closing portion 50A entersinto the recess portion 30A located at the outer side of the screwbosses 32 (see FIG. 5A). The door 50 moves (rotates) substantiallyrearward along the guide grooves 42 to open the opening 20 (see FIG.5B). When an outer peripheral face of a distal end vicinity of theclosing portion 50A has reached a vicinity of an inner side of the screwbosses 36, the opening 20 is completely opened (see FIG. 5C). When theopening 20 is open, the door 50 can close the opening 20 by rotatingsubstantially in the opposite direction.

[0073] Thus, the door 50 is formed to be curved so as to open and closethe opening 20 by rotating along a movement path thereof withoutdeviating from the predetermined circular circumference. The center andradius of rotation of the door 50 (the shape of the guide grooves 42)can be suitably determined in accordance with positions of the front andrear edge portions of the opening 20 (the screw bosses 32 and 36), whichare determined by requirements of the drive device, with an angle of theopening face of the opening 20, which is determined by requirements ofthe library apparatus, and the like.

[0074] A plurality of protrusion portions 51 are protrudingly providedat upper and lower ends of the door 50 and enter into the upper andlower guide grooves 42, respectively. The protrusion portions 51 havedifferent protrusion heights from the closing portion 50A and the drivenportion 50B, but distances from a breadth direction center line of thedoor 50 (along the length direction thereof) to peak portions of theprotrusion portions 51 are constant. Thus, the upper and lowerprotrusion portions 51 slide against the ceiling plate 16B and the floorplate 18B, which are floor portions of the guide grooves 42.

[0075] Protrusions 51A are protrudingly provided at the protrusionportions 51, at both sides in the plate thickness direction of the door50 (see FIGS. 5A to 5C). Peak portions of the protrusions 51A are inline with plate thickness direction faces of the door 50. Theprotrusions 51A slide against the groove walls of the guide grooves 42(the ribs 44 and the like). The protrusion portions 51 that are locatedfurthest toward the front are disposed so as to enter into the taperingopening 20A, which communicates with the guide grooves 42, during theopening/closing process of the opening 20.

[0076] Because of the protrusion portions 51 and the protrusions 51A,the door 50 is a structure which is guided in the guide grooves 42 whenopening/closing the opening 20, and reliably moves to open by threadingbetween the right wall 12B and the free play-restricting walls 28, atthe outer side of the screw bosses 32 and the inner side of the screwbosses 36, without deviating from the aforementioned movement paththereof.

[0077] At an outer peripheral portion of the door 50, at a front endvicinity (the closing portion 50A side) of the driven portion 50B, theoperation projection 52 projects along a diametric direction of the door50, to serve as an operation portion. The operation projection 52 isexposed to the outside of the case 12 through the slit 40. With theoperation projection 52 of this structure, in accordance with loading(relative movement) of the recording tape cartridge 10 into the drivedevice, an engagement protrusion 104 advances in through the portion ofthe slit 40 which opens frontward, engages with the operation projection52, and moves the door 50 in the direction of opening the opening 20.

[0078] A spring-holding portion 54, which has the form of a substantialL-shape toward an inner face side of the door 50, is protrudinglyprovided at a rear end portion of the driven portion 50B of the door 50.The spring-engaging portion 54 has a free end at an upper end sidethereof. The coil spring 56, which serves as an urging means, is engagedand retained at the spring-engaging portion 54. Specifically, theannular portion 56A and an annular portion 56B are provided atrespective end portions of the coil spring 56 for engagement. Theannular portion 56A is passed through by the spring-engaging pins 55 ofthe case 12 and is engaged and retained at the case 12, and the annularportion 56B is passed through by the spring-engaging portion 54 and isengaged and retained at the door 50.

[0079] Accordingly, in this structure, the door 50 is urged in thedirection of closing the opening 20 by urging force of the coil spring56, and the door 50 usually closes the opening 20. The coil spring 56has a length that reaches as far as the rear-right corner portion of thecase 12 in the state in which the door 50 closes the opening 20 asdescribed above. Thus, the coil spring 56 is disposed so as toeffectively utilize a space between the free play-restricting walls 28and the peripheral walls 16A and 18A (the rear wall 18C) at therear-right corner portion.

[0080] Stoppers 58 are protrudingly provided at the inner face of theclosing portion 50A of the door 50. The stoppers 58 abut against anupper end portion side face and a lower end portion side face of theleader pin 22 when the opening 20 is closed. Thus, detachment of theleader pin 22 from the pin stands 24 by falling impacts and the like canbe reliably prevented.

[0081] With the door 50 of the structure described above, the operationprojection 52 is engaged with the engagement protrusion 104 of the drivedevice by an operation of loading the recording tape cartridge 10 intothe drive device (see FIGS. 5A to 5C). Thus, the door 50 moves relativeto the case 12, against the urging force of the coil spring 56, andopens the opening 20. At a time of ejection from the drive device, theopening 20 is closed by the urging force of the coil spring 56.

[0082] Further, the door 50, which is curvedly formed in the circulararc shape, is rotated to open and close the opening 20, which is angledwith respect to the direction of arrow A, by swinging around an outerside of the reel 14 and the pin stands 24 (and the leader pin 22)without deviating from the movement path along the shape of thecurvature. Thus, the door 50 is a structure which will not protrudebeyond an external profile region of the case 12 during opening andclosing of the opening 20.

[0083] Structure of Reel and Brake Structure

[0084] As is shown in FIGS. 2 and 6, the reel 14 is provided with a reelhub 60 with the form of a substantially circular tube with a base. Thereel hub 60 includes a tubular portion 60A and a base portion 60B. Themagnetic tape T is wound onto the tubular portion 60A at an outerperipheral face thereof. The base portion 60B closes off a lower portionof the tubular portion 60A. At a vicinity of the base portion 60B sideend portion (lower end portion) of the reel hub 60, a lower flange 62 iscoaxially and integrally provided at the diametric direction outer sideof the reel hub 60. Further, an upper flange 64 is coaxially joined toan upper end portion of the reel hub 60 by ultrasonic welding or thelike. An internal diameter of the upper flange 64 is set to besubstantially the same as an internal diameter of the tubular portion60A, and an external diameter of the upper flange 64 is set to be thesame as an external diameter of the lower flange 62.

[0085] Thus, at the reel 14, the magnetic tape T is wound round theouter peripheral face of the tubular portion 60A of the reel hub 60between opposing faces of the lower flange 62 and the upper flange 64,and the tubular portion 60A opens upward. The external diameter of thelower flange 62 and the upper flange 64 is set to be slightly smallerthan an internal diameter of the free play-restricting walls 28 of thecase 12. Thus, the reel 14 is rotatable inside the case 12.

[0086] As shown in FIG. 7, a lower peripheral portion of the baseportion 60B of the reel hub 60 protrudes slightly beyond a lower face ofthe lower flange 62, and the reel gear 66, which is formed in an annularshape, is provided at an outer peripheral vicinity of a lower end faceof the base portion 60B. The reel gear 66 is specified so as to bemeshable with a driving gear 102, which is provided at a distal end of arotation shaft 100 of the drive device.

[0087] Through-holes 68, which pass through the base portion 60B (andthe reel gear 66) are provided at three locations, which are equallyspaced, on a circular periphery at the portion at which the reel gear 66is disposed. A diameter of each through-hole 68 is greater than a gearpitch of the reel gear 66, and the teeth of the reel gear 66 are notprovided in a vicinity of each through-hole 68.

[0088] A reel plate 70, which is an annular plate formed of a magneticmaterial which is capable of adsorption by magnetism, is provided at thelower end face of the base portion 60B of the reel hub 60, at the innerside of the reel gear 66. The reel plate 70 is provided integrally byinsert-molding.

[0089] The lower end portion of the base portion 60B of the reel hub 60,which protrudes beyond the lower flange 62, is inserted (fitted withplay) into the gear aperture 26 of the case 12 in a state in which adiametric direction inner end portion of the lower flange 62 abutsagainst an upper end portion of the annular rib 26A. Thus, the reel gear66 and the reel plate 70 are exposed to outside the case 12.

[0090] Pairs of engaging protrusions 72 (six protrusions in total) arestandingly provided at an upper face of the base portion 60B of the reelhub 60 (see FIG. 2). The engaging protrusions 72 are equally spaced onthe circular periphery, at three locations between the respectivethrough-holes 68. The engaging protrusions 72 respectively serve asengaging portions in the present invention. Gear teeth 72A are formed atdistal end portions (upper end portions) of the engaging protrusions 72(see FIG. 8). These gear teeth 72A are capable of meshing with a brakegear 74A of a brake member 74, which is described later.

[0091] The recording tape cartridge 10 is further equipped with a brakestructure for blocking rotation of the reel 14 at times of non-use. Thisbrake structure is equipped with the brake member 74, which serves as a‘brake member’ of the present invention. The brake member 74 is providedwith a disc portion 76, which is formed in a substantially circularplate shape. The brake gear 74A, which is meshable with the gear teeth72A of the reel 14, is formed in an annular shape at an outer peripheralvicinity of a lower end face of the disc portion 76.

[0092] As shown in FIG. 2, the brake member 74 is provided with anX-form protrusion 78, which is formed substantial in a cross shape inplan view and is provided standing from an upper face of the discportion 76. At an interior portion of the X-form protrusion 78, aninsertion channel 78A is formed in a shape corresponding to the X-formprotrusion 78. In other words, the X-form protrusion 78 structureschannel walls of the insertion channel 78A. A spring-holding recessportion 80 is also formed at the upper face of the disc portion 76, atan outer side of the X-form protrusion 78. The spring-holding recessportion 80 is surrounded by a wall portion with an annular shape in planview.

[0093] At this brake member 74, the disc portion 76, at which the brakegear 74A and the spring-holding recess portion 80 of are provided, andthe X-form protrusion 78, in which the insertion channel 78A is formed,are integrally formed by resin-molding, and correspond to a main body ofthe brake member of the present invention. In addition, the brake member74 is provided with a rubbing protrusion portion 82, which is structuredby a metallic member and is embedded at an axial center lower portion ofthe disc portion 76.

[0094] A rubbing surface 82A of the rubbing protrusion portion 82protrudes downward relative to the lower face of the disc portion 76(see FIG. 9). The rubbing protrusion portion 82 structures a portion ofthe brake member 74 that abuts against a release pad 90, which isdescribed later. Details thereof will be given later.

[0095] The brake member 74 described above is insertedly disposed in thetubular portion 60A of the reel hub 60 so as to be movable in a verticaldirection (an axial direction of the reel 14) and substantially coaxialwith the tubular portion 60A. Thus, when the brake member 74 moves inthe vertical direction, the brake gear 74A of the brake member 74 canattain a position at which the brake gear 74A meshes with the gear teeth72A of the engaging protrusions 72 provided at the reel hub 60 (arotation-locking position) or a position at which this meshing isreleased (a rotation-enabling position).

[0096] An X-form rib 84 (see FIGS. 3 and 6), which serves as an engagingprotrusion, is provided protruding downward from the ceiling plate 16Bof the case 12. The X-form rib 84 enters into the insertion channel 78Aof the X-form protrusion 78 of the brake member 74. With this structure,rotation of the brake member 74 relative to the case 12 is blocked byengagement of the X-form protrusion 78 (i.e., the channel walls of theinsertion channel 78A) with the X-form rib 84.

[0097] Accordingly, in a state in which the brake member 74 is disposedat the rotation-locking position and the brake gear 74A is meshed withthe gear teeth 72A of the reel hub 60, rotation of the reel 14 isblocked. The X-form rib 84 is maintained in a state of being inserted inthe X-form protrusion 78 over the whole of a movement stroke of thebrake member 74 in the vertical direction. Thus, this is a structurewhich provides a function of guiding directions of movements of thebrake member 74 to the vertical direction.

[0098] A compression coil spring 86, which serves as an ‘urgingstructure’ of the present invention, is disposed between thespring-holding recess portion 80 of the brake member 74 and the ceilingplate 16B. One end portion of the compression coil spring 86 is fittedinto the spring-holding recess portion 80 and the other end portion isfitted inside an annular wall portion 88, which is provided protrudingfrom the ceiling plate 16B. Thus, the compression coil spring 86 willnot be displaced in diametric directions thereof.

[0099] In this structure, as shown in FIG. 7, the brake member 74 isurged downward by urging force of this compression coil spring 86, thebrake gear 74A is meshed with the gear teeth 72A, and the brake gear 74Areliably prevents undesired rotation of the reel 14 (i.e., the brakemember 74 is disposed at the rotation-locking position). Also due tothis urging force, the reel 14 whose engaging protrusions 72 are meshedwith the brake member 74 is urged downward and, as mentioned earlier,the lower flange 62 abuts against the annular rib 26A such that the reel14 is not loose inside the case 12.

[0100] The release pad 90, which serves as a release member of thepresent invention, is disposed between the base portion 60B and thebrake member 74 inside the reel hub 60 (the tubular portion 60A) of thereel 14. The release pad 90 is formed in a flat plate form with asubstantially equilateral triangle shape in plan view. Three circularcolumn-form leg portions 92 are provided protruding from a lower face ofthe release pad 90 at a vicinity of each corner portion thereof. The legportions 92 correspond, respectively, with the through-holes 68 of thebase portion 60B.

[0101] A rubbing protrusion portion 94 is provided at a central portionof an upper face of the release pad 90. The rubbing protrusion portion94 abuts against the rubbing protrusion portion 82 of the brake member74. Details of the rubbing protrusion portion 94 will be given later.

[0102] In a state in which the leg portions 92 are inserted through thethrough-holes 68, so as to be movable in the vertical direction, therelease pad 90 rests on the base portion 60B of the reel hub 60 so asnot to interfere with the engaging protrusions 72 (the lower face of therelease pad 90 abuts against the upper face of the base portion 60B). Inthis state, the leg portions 92 protrude beyond lower end portions ofthe through-holes 68 such that distal ends of the leg portions 92 are atsubstantially the same level as tooth peaks of the reel gear 66. Thus,in this structure, when the rubbing protrusion portion 94 abuts againstthe rubbing protrusion portion 82 of the brake member 74, the releasepad 90 is maintained in this state, in which the leg portions 92 areprotruding, by the urging force of the compression coil spring 86.

[0103] However, if the leg portions 92 are pushed to move upward againstthe urging force of the compression coil spring 86, the release pad 90pushes the brake member 74, which is abutting against the rubbingprotrusion portion 94 of the release pad 90, upward and releases themeshing of the brake member 74 with the gear teeth 72A of the engagingprotrusions 72 (i.e., moves the brake member 74 to the releaseposition).

[0104] Specifically, as shown in FIG. 8, at a time when the driving gear102 meshes with the reel gear 66 of the reel 14, the rotation shaft 100is relatively moving in an upward direction with respect to the case 12,and thus the leg portions 92 of the release pad 90 are pushed by toothpeaks of the driving gear 102.

[0105] Thus, in accordance with an operation of meshing the driving gear102 with the reel gear 66, the reel 14 rises in the case 12 against theurging force of the compression coil spring 86 (i.e., the lower flange62 is separated from the annular rib 26A), the rotation-locking statecaused by the brake member 74 is released, and the reel 14 becomesrotatable in the case 12. In other words, the release pad 90 is astructure which moves the brake member 74 to the rotation-enablingposition in accordance with the operation of meshing the driving gear102 with the reel gear 66, and in states in which the meshing of thedriving gear 102 with the reel gear 66 is maintained (at times of use ofthe recording tape cartridge 10), holds the brake member 74 at therotation-enabling position.

[0106] In this state, the leg portions 92 of the release pad 90 aredisposed inside the through-holes 68 of the reel hub 60. Thus, with thisstructure, the release pad 90 rotates (integrally) with the reel 14 whenthe rotation shaft 100 rotates.

[0107] Therefore, the brake member 74 and the release pad 90 relativelyrotate during rotation of the reel 14, and the rubbing protrusionportions 82 and 94, which are abutting portions of the brake member 74and the release pad 90 rub against one another. Now, the rubbingprotrusion portions 82 and 94 will be described.

[0108] As shown in FIG. 9, the rubbing protrusion portion 82, which isthe metallic member that is embedded at the axial center lower portionof the disc portion 76 and structures the brake member 74, is formed ina short circular column shape, and the rubbing surface 82A, which is theone end face of the rubbing protrusion portion 82 that protrudes beyondthe lower face of the disc portion 76, is formed as a convexly curvedsurface. Specifically, the rubbing surface 82A is structured as a convexspherical surface with a spherical radius r of at least 14 mm, and apeak portion X thereof coincides with the axial center of the brakemember 74. The rubbing surface 82A is finished to a mirror surface (withhigh gloss).

[0109] The rubbing protrusion portion 82 at which this rubbing surface82A is formed is fixed in the state of being embedded in the discportion 76 by pressure insertion or insert-molding. Thus, the rubbingprotrusion portion 82 is structured such that rotation relative to thedisc portion 76 does not occur. For a metallic material that structuresthis rubbing protrusion portion 82, for example, stainless steel may beemployed.

[0110] Meanwhile, the rubbing protrusion portion 94 is formed in a shortcircular column shape, and a rubbing surface 94A, which is an upper endface thereof, is formed as a flat surface. This rubbing protrusionportion 94 is structured of a resin material, and is formed integrallywith the release pad 90 by resin-molding.

[0111] Because of the above, the rubbing surface 82A, which is theconvex spherical surface of the rubbing protrusion portion 82, and therubbing surface 94A, which is the flat surface of the rubbing protrusionportion 94, are substantially in point contact at the peak portion X ofthe rubbing surface 82A, and this structure alleviates frictionalresistance during the aforementioned relative rotation. Thus, with thisstructure, the peak portion X, which is the position of point contact,coincides with the axial center of the brake member 74. Further, in thisstructure, the peak portion X coincides with the center of rotation ofthe reel 14, which is to say a center of rotation of the rubbingprotrusion portion 94, and, because the convex spherical surface and theflat surface are in point contact, the state in which the peak portion Xcoincides with the above-mentioned center of rotation is easilymaintained (i.e., resistant to mispositioning).

[0112] Next, operation of the first embodiment will be described.

[0113] In the recording tape cartridge 10 having the structure describedabove, the door 50 is entered into the recess portion 30A by the urgingforce of the coil spring 56 and closes the opening 20 when the recordingtape cartridge 10 is not in use (during storage, during transportation,and the like).

[0114] As shown in FIG. 7, the urging force of the compression coilspring 86 is transmitted through the brake member 74 which is meshedwith the engaging protrusion 72 (and through the release pad 90) to thereel 14. As a result, the lower flange 62 is pressed (abutted) againstthe annular rib 26A and the reel gear 66 is exposed through the gearaperture 26.

[0115] Thus, the brake gear 74A of the brake member 74 is meshed withthe gear teeth 72A of the engaging protrusions 72 by the urging force ofthe compression coil spring 86, and rotation of the reel 14 with respectto the case 12 is blocked. In other words, the brake member 74 isdisposed at the rotation-locking position.

[0116] In contrast, when the magnetic tape T is to be used, therecording tape cartridge 10 is loaded into a bucket (not shown) of adrive device along the direction of arrow A. In accordance with thisloading, the engaging protrusion 104 (see FIGS. 5A to 5C), which isfixed at the bucket, engages with the operation projection 52 of thedoor 50. Hence, the door 50 rotates substantially rearward and opens theopening 20.

[0117] Then, when the recording tape cartridge 10 has been loaded to apredetermined depth in the drive device, the bucket descends, and therotation shaft 100 of the drive device relatively approaches (movesupward) toward the gear aperture 26 of the case 12 and retains the reel14. Specifically, the rotation shaft 100 adsorbs and retains the reelplate 70 by means of, for example, an electromagnet (not shown) which isdisposed at a distal end portion of the rotation shaft 100, and thedriving gear 102 of the rotation shaft 100 is meshed with the reel gear66.

[0118] In accordance with the meshing of the reel gear 66 with thedriving gear 102, tooth peaks of the driving gear 102 abut against thedistal ends (lower end faces) of the leg portions 92 of the release pad90, and push the release pad 90 upward against the urging force of thecompression coil spring 86. As a result, the brake member 74, whichabuts against the release pad 90 at the rubbing protrusion portion 82,also moves upward, and the meshing of the brake gear 74A of the reelplate 70 with the gear teeth 72A of the engaging protrusions 72 isreleased.

[0119] When the rotation shaft 100 moves further upward, the reel 14pushes the release pad 90 and the brake member 74 up together (i.e.,without changing relative positions thereof), against the urging forceof the compression coil spring 86, and the lower flange 62 moves awayfrom the annular rib 26A. As a result, the reel 14 rises in the case 12and becomes rotatable, in a state of non-contact with inner faces of thecase 12.

[0120] In this state, in which the recording tape cartridge 10 has beenpositioned within the drive device by the descent of the bucket, thedrawing-out means of the drive device draws out the leader pin 22through the opened opening 20, and accommodates the leader pin 22 at awinding reel of the drive device. Then, the winding reel and the reel 14(the rotation shaft 100) are driven to rotate synchronously by the drivedevice, and the magnetic tape T is wound around the winding reel whilebeing sequentially drawn out from the case 12. Informationrecording/replaying is carried out on the magnetic tape T by arecording/replaying head or the like which is disposed along apredetermined tape path.

[0121] At this time, the rubbing protrusion portion 82 of the brakemember 74 which is not rotatable with respect to the case 12 rubs, atthe peak portion X of the rubbing surface 82A of the rubbing protrusionportion 82, against the rubbing surface 94A of the rubbing protrusionportion 94 of the release pad 90 which, together with the reel 14,rotates relative to the case 12.

[0122] Subsequently, when the magnetic tape T has been wound back to thereel 14 again and the leader pin 22 has been retained at the pin stands24, the magnetic force of the above-mentioned magnet is turned off, theadsorption of the rotation shaft 100 with the reel plate 70 is released,and the bucket in which the recording tape cartridge 10 is loaded rises.

[0123] Accordingly, the meshing of the reel gear 66 with the drivinggear 102 is released, and the abutting of the driving gear 102 againstthe leg portions 92 of the release pad 90 is released. Thus, the releasepad 90 is moved downward together with the brake member 74 (whilemaintaining the abutting state thereof) by the urging force of thecompression coil spring 86.

[0124] Hence, the leg portions 92 of the leg portions 92 respectivelyprotrude through the through-holes 68 as far as the level at which thereel gear 66 is formed, and the brake gear 74A of the brake member 74meshes with the gear teeth 72A of the engaging protrusions 72. That is,the brake member 74 returns to the rotation-locking position forblocking rotation of the reel 14.

[0125] Further, in accordance with the operation of moving the brakemember 74 and the release pad 90 by the urging force of the compressioncoil spring 86, the reel 14 also moves downward, and returns to theinitial state thereof, in which the lower flange 62 of the reel 14 abutsagainst the annular rib 26A and the reel gear 66 is exposed through thegear aperture 26.

[0126] When the recording tape cartridge 10 is to be ejected from thebucket, the recording tape cartridge 10 is moved in the directionopposite to the direction of arrow A by the urging force of the coilspring 56 and/or by an unillustrated ejection mechanism. In accordancewith this movement, the door 50 closes the opening 20 due to the urgingforce of the coil spring 56. Thus, the recording tape cartridge 10 isejected from the drive device and returns to the initial state thereof.

[0127] Now, in the recording tape cartridge 10, when the reel 14 isrotating, the brake member 74 and the release pad 90 rub together atmutually abutting portions thereof, which are the metallic rubbingsurface 82A and the resin rubbing surface 94A. Therefore, rubbing(sliding) resistance in accordance with this rubbing contact is small,and heat generation at the abutting portions is suppressed. Inparticular, because the rubbing surface 82A is in point contact with therubbing surface 94A, at the peak portion X, this rubbing resistance isfurther alleviated, and heat generation at this rubbing contact portionis further suppressed. Moreover, because the rubbing protrusion portion82 is structured of a metallic material with high heat conductivity,heat that is generated at the rubbing contact (point contact) portion isconducted within the metallic member that structures the rubbingprotrusion portion 82 and is radiated to the exterior thereof, and arise in temperature at the rubbing contact portion is suppressed.Therefore, even under conditions in which the rotation speed of the reel14 is higher and the duration of rotation is longer, melting of theresin side rubbing protrusion portion 94 in accordance with the rubbingof the rubbing surface 82A against the rubbing surface 94A will notoccur.

[0128] Further, the structure that makes the rubbing contact portion apoint contact is effected by the metal side rubbing surface 82A beingformed as a convex spherical surface whose peak portion X coincides withthe axial center of the brake member 74 and the resin side rubbingsurface 94A being formed as a flat surface. In other words, rather thanthe resin side rubbing surface 94A being made to be a protrudingsurface, which would be susceptible to abrasion or wearing, the rubbingsurface 82A is set to a convex spherical surface with a spherical radiusof at least 3 mm, which has low impact effect (or invasive effect) onthe resin side rubbing surface 94A. Therefore, even under the conditionsin which the rotation speed of the reel 14 is higher and the rotationduration is longer, abrasion or wearing of the resin side rubbingsurface 94A in accordance with the aforementioned rubbing contact isgreatly suppressed. In particular, in this first embodiment, because themetal side rubbing surface 82A is made to be a convex spherical surfacewhose radius r is at least 14 mm, impact effect by the rubbing surface82A on the resin side rubbing surface 94A is further reduced, andabrasion and wearing of the rubbing surface 94A are reliably prevented.

[0129] Specifically, in results of a test of continuous rotation forseveral hundred hours, corresponding to an acceleration test, at amaximum speed of rotation of the reel 14 in a case in which a feedingspeed of the magnetic tape T was set to 6 m/s, melting and abrasion(wearing) of the resin side rubbing protrusion portion 94 were notobserved at all.

[0130] Accordingly, the position relative to the case 12 of the brakemember 74, which is urged downward by the compression coil spring 86, isfixedly maintained at both the rotation-locking position and therotation-enabling position. That is, the height level of the rubbingprotrusion portion 94 is not reduced in accordance with melting,abrasion or the like of the rubbing protrusion portion 94. Therefore, aninsertion length (engagement amount) of the X-form rib 84 of the case 12in the insertion channel 78A of the brake member 74 will not be reduced.Thus, looseness of the brake member 74, mispositioning of the peakportion X with respect to the rotation center of the reel 14, and thelike are prevented. Accordingly, generation of noise and the like inaccordance with mispositioning of the peak portion X or the like isprevented.

[0131] Thus, with the recording tape cartridge 10 relating to the firstembodiment, melting, abrasion and the like at the region of abutting ofthe brake member 74 with the release pad 90 will not occur duringrotation of the reel 14.

[0132] Further, with this recording tape cartridge 10, the brake member74 is structured with the rubbing protrusion portion 82 (the rubbingsurface 82A), which is a metallic member, embedded in the disc portion76, which is fabricated of resin. Therefore, the brake member 74 can beeasily provided with a complex shape, while a function of preventingmelting, abrasion and the like of the resin side rubbing surface 94A ismaintained. That is, the brake gear 74A, the X-form protrusion 78 (andthe insertion channel 78A) and the like of the brake member 74 can beprovided with ease by resin-molding. In particular, the brake gear 74A,which would be high in cost if machined from metal, can be provided atlow cost by resin-molding. Furthermore, an increase in weight of thebrake member 74 (and hence of the recording tape cartridge 10) inaccordance with the rubbing protrusion portion 82 being made metal canbe suppressed.

[0133] As described above, the present invention is based on the finding(experimental result) that, when a metal is rubbed against a resin inorder to reduce rubbing resistance between members that are relativelyrotating while abutting, abrasion and wearing of the resin side rubbingsurface can be prevented or greatly suppressed by making the metal siderubbing surface (the rubbing surface 82A) a convex spherical surfacewith a spherical radius of not less than 3 mm (which includes the caseof a flat surface whose radius is infinitely large), and not making theresin side rubbing surface (the rubbing surface 94A) a protruding form.Numerous variations based only on this finding are possible.

[0134] Herebelow, some variant examples will be described on the basisof FIGS. 10A to 10D. Note that components and portions that are inessence the same as in the first embodiment are assigned the samereference numerals as in the first embodiment, and descriptions thereofare omitted.

[0135] In a first variant example shown in FIG. 10A, the rubbingprotrusion portion 94 (and the rubbing surface 94A) is not provided atthe release pad 90. Rather, a flat upper face of the release pad 90serves as a rubbing surface 106 which rubs against the rubbing surface82A. Naturally, all the same effects as in the first embodiment areprovided by a structure relating to this first variant example.

[0136] In a second variant example shown in FIG. 10B, a rubbing recessportion 108 is formed at an axial center portion of the release pad 90.A flat bottom surface of this rubbing recess portion 108 serves as arubbing surface 108A which rubs against the rubbing surface 82A. Therubbing recess portion 108 is formed in a circular shape in plan view,and a distal end portion of the rubbing protrusion portion 82 is enteredinto the rubbing recess portion 108 such that a recess wall (innerperipheral face) 108B of the rubbing recess portion 108 faces an outerperipheral face 82B of the rubbing protrusion portion 82. With astructure relating to this second variant example, all the same effectsas in the first embodiment are provided, in addition to which therubbing recess portion 108 of the release pad 90 effects a function ofrestricting mispositioning of the brake member 74 in the diametricdirection. Note that this effect could also be provided by providing anannular rib encircling the above-mentioned rubbing surface 106 insteadof providing the rubbing recess portion 108.

[0137] In a third variant example shown in FIG. 10C, a rubbing surface110, which is a curvedly recessed surface, is formed at the axial centerportion of the release pad 90. The rubbing surface 110 has a sphericalradius R which is larger than the radius r of the rubbing surface 82A,and is formed as a concave spherical surface whose center is located ata position through which the axial center of the release pad 90 (therotation center of the reel 14) passes. Thus, in a structure relating tothis third variant example too, the rubbing surface 82A is in pointcontact with the rubbing surface 110 at the peak portion X thereof.Therefore, with a structure relating to this third variant example, allthe same effects as in the first embodiment are provided, in addition towhich, because the rubbing surface 110 has a form which accommodates therubbing surface 82A, offsetting of the axial center of the release pad90 and the peak portion X, which is the portion of the brake member 74that mutually abuts (rubs) against the release pad 90, is even lesslikely (i.e., an alignment function is effected).

[0138] In a fourth variant example shown in FIG. 10D, instead of therubbing protrusion portion 82, the brake member 74 is provided with arubbing protrusion portion 112 with a short circular column formincluding a rubbing surface 112A, which is a flat surface. That is, therubbing protrusion portion 112 is a structure whose radius of curvatureis set to be infinitely large (r=∞), and the peak portion X is notformed. Thus, the brake member 74 rubs against the rubbing surface 94Aof the release pad 90 at the rubbing surface 112A. Hence, rubbingresistance in this case is larger than in a case of point contact, butheat that is generated does not act in a localized manner. Therefore,the resin side rubbing surface 94A will not melt. Further, because themetal side rubbing surface 112A does not have a protruding form, impact(or invasive) effect thereof on the rubbing surface 94A is furtherreduced, and the corresponding resin side rubbing surface 94A will notbe abraded or worn. Thus, with a structure relating to this fourthvariant example too, all the same effects as in the first embodiment areprovided. Note that an outer edge portion of the rubbing surface 112Ahas a curved form which is continuous with an outer peripheral face ofthe rubbing protrusion portion 112. Thus, damage to the rubbing surface94A by an edge or the like is prevented.

[0139] Next, a recording tape cartridge 120 relating to a secondembodiment of the present invention will be described. Note thatcomponents and portions that are in essence the same as in the firstembodiment are assigned the same reference numerals as in the firstembodiment, and descriptions thereof are omitted.

[0140]FIG. 11 shows a sectional view, corresponding to FIG. 7, of therecording tape cartridge 120, and FIG. 12 shows another sectional view,corresponding to FIG. 8, of the recording tape cartridge 120. As shownin these drawings, the recording tape cartridge 120 differs from therecording tape cartridge 10 relating to the first embodiment in that therelease pad 90 is not provided. Herebelow, this point is explained indetail.

[0141] Instead of the engaging protrusions 72, a reel brake gear 122 isprovided in a circular annular form at the upper face of the reel hub 60of the reel 14, which structures the recording tape cartridge 120. Thereel brake gear 122 serves as an engaging portion which is capable ofmeshing with the brake gear 74A of the brake member 74. Because of this,it is not necessary to provide a space for disposition of the releasepad 90 between the base portion 60B and the brake member 74.

[0142] A through-hole 124 is formed in the base portion 60B, whichpenetrates through the axial center portion of the base portion 60B. Thethrough-hole 124 is for insertion of a release-pushing portion 132,which is described below. Thus, the through-hole 124 mutuallycommunicates with a through-hole 70A of the annular reel plate 70 (whichthrough-hole 70A was not discussed for the first embodiment).

[0143] Hence, in a state in which the brake member 74 is disposed at therotation-locking position and the brake gear 74A is meshed with the reelbrake gear 122, the rubbing protrusion portion 82 of the brake member 74is disposed in the through-hole 124 of the reel hub 60, and facesthrough the through-hole 70A of the reel plate 70 to outside the case12.

[0144] Correspondingly, at an axial center portion of a rotation shaft130 of a drive device that corresponds with the recording tape cartridge120, the release-pushing portion 132, which serves as a release portion,is provided protruding upward. An upper end face of the release-pushingportion 132 serves as a flat rubbing surface 132A. A tapering wall 134,with an internal diameter which broadens toward the upper side, isprovided around the rubbing surface 132A. This tapering wall 134functions similarly to the aforementioned recess wall 108B. At thisrotation shaft 130, the driving gear 102, the release-pushing portion132 (and the rubbing surface 132A) and the tapering wall 134 areintegrally formed by resin-molding. Thus, the rubbing surface 132A ofthe release-pushing portion 132 is formed of resin as a flat surface.

[0145] When the recording tape cartridge 120 relating to the secondembodiment is loaded in a drive device and a bucket thereof descends,the driving gear 102 of the rotation shaft 130 meshes with the reel gear66 of the reel 14. In accordance with this operation, therelease-pushing portion 132 advances into the through-hole 124 (and thethrough-hole 70A), and the release-pushing portion 132 abuts against therubbing protrusion portion 82 of the brake member 74 while pushing thesame upward. Accordingly, the brake member 74 moves upward against theurging force of the compression coil spring 86 and, as shown in FIG. 12,the brake member 74 moves to the rotation-enabling position and releasesthe state of meshing of the reel brake gear 122 with the brake gear 74A.Hence, in a state in which the meshing of the reel gear 66 with thedriving gear 102 is maintained, the brake member 74 abuts against therelease-pushing portion 132 of the rotation shaft 130, and is maintainedat the rotation-enabling position.

[0146] In this state, when the rotation shaft 130 rotates and drives thereel 14 to rotate, the brake member 74, which is incapable of rotationrelative to the case 12, and the release-pushing portion 132 of therotation shaft 130, which meshes with the reel 14 and drives the same torotate, relatively rotate. Hence, because of this relative rotation, themutually abutting rubbing surface 82A and rubbing surface 132A rubtogether. More specifically, the rubbing surface 82A rubs against therubbing surface 132A, which is a flat surface, at the peak portion X.

[0147] With the recording tape cartridge 120 relating to the secondembodiment, in accordance with the finding described earlier, the resinside rubbing contact portion, which rubs against the rubbing surface 82Aformed of metal at the brake member 74 during rotation of the reel 14,is formed simply by the rubbing surface 132A of the release-pushingportion 132 at the drive device side (outside the recording tapecartridge 120), instead of by the rubbing surface 94A of the release pad90. Consequently, the recording tape cartridge 120 too provides all thesame effects as the recording tape cartridge 10 relating to the firstembodiment.

[0148] Thus, with the recording tape cartridge 120, melting, abrasionand the like at the region of abutting of the brake member 74 with therelease-pushing portion 132 of the drive device will not occur duringrotation of the reel 14.

[0149] Note that the present invention is not limited to the embodimentsand the first to fourth variant examples described above. Within a rangebased on the finding mentioned above, various embodiments in which someor all of the characteristic structural elements of these embodimentsare suitably combined can be used. Thus, for example, the rubbingsurface 10 which is a concave spherical surface could be formed at theupper face of the rubbing protrusion portion 94, the lower face of therubbing recess portion 108 or the like, and/or the radius r of therubbing surface 82A could be made to match the radius R of the rubbingsurface 110 such that these could be surface-contacted. Further, it ispossible to provide the rubbing surface 110 at the upper end of thedrive device side release-pushing portion 132. Furthermore, given theaforementioned finding that abrasion and the like of the resin side at arubbing contact portion between resin and metal is prevented by notgiving the resin side a protruding form but giving the metal side a flatsurface or a convex spherical surface with a radius of at least 3 mm,obviously, cases in which the rubbing surface 94A, the rubbing surface108A, the release-pushing portion 132 or the like is fabricated of metalwith a convex spherical surface with a radius of at least 3 mm and therubbing contact portion of the brake gear 74A is fabricated of resin asa flat surface or a concave spherical surface (such as the rubbingsurface 110) are included.

[0150] Further still, in the embodiments and variant examples describedabove, the rubbing surface 82A has been structured to be a convexspherical surface as a whole. However, the present invention is notlimited thus. For example, in a case in which the rubbing surface 82Arubs against the opposing element at the peak portion X, it issufficient if the rubbing protrusion portion 82 has a smooth form in theimmediate neighborhood of the peak portion X that resembles a convexspherical surface with a radius of at least 3 mm.

[0151] Further again, with a recording tape cartridge relating to thepresent invention, it is sufficient that the brake member 74 or thelike, which can attain the rotation-locking position and therotation-enabling position, is maintained at the rotation-enablingposition by the release pad 90, the release-pushing portion 132 or thelike during use; the present invention is not limited by shapes and thelike of the brake member 74, the release pad 90 and the release-pushingportion 132. Moreover, the present invention is, obviously, not limitedby preferable structures of the opening 20, the door 50 and the like.

[0152] Further yet, in the embodiments and variant examples describedabove, structures in which a magnetic tape T is employed as therecording tape are used. However, the present invention is not limitedthus. It is sufficient that the recording tape is one of long tape-forminformation recording/replaying media which can record information andreplay information that has been recorded. Of course, the recording tapecartridge relating to the present invention can be applied to recordingtape of any kind of recording/replaying system.

[0153] As has been explained above, a recording tape cartridge relatingto the present invention has excellent effects in that melting, abrasionand the like do not occur at an abutting portion of a brake member witha release member, or with a release portion of a drive device, duringrotation of a reel.

What is claimed is:
 1. A tape cartridge which is insertable at a tapedrive which includes a rotating member and carries out at least one ofreading and writing of data, the tape cartridge comprising: a reelinside the tape cartridge, the rotating member of the tape drive beingengageable with the reel at a time of insertion of the tape cartridge,for transmitting rotary driving force to the reel; a brake member whichis reciprocally movable between a locking position for prohibitingrotation of the reel and an unlocking position for enabling rotation ofthe reel; and a release pad which is capable of engaging with therotating member and abutting against the brake member for moving thebrake member to the unlocking position, wherein one of mutually abuttingportions of the brake member and the release pad includes a metallicsurface which includes one of a flat surface form and a spherical formwith a spherical radius of at least 3 mm, and the other of the mutuallyabutting portions includes a resin surface which includes one of a flatsurface form and a curvedly recessed surface form.
 2. The tape cartridgeof claim 1, wherein the one abutting portion includes a metallic surfacethat includes a spherical form with a spherical radius of at least 14mm, and the other abutting portion includes a resin surface with acurvedly recessed surface form that includes a spherical radius equal toor greater than the radius of the one abutting portion.
 3. The tapecartridge of claim 1, further comprising an urging member whichcontinuously urges the brake member toward the locking position.
 4. Thetape cartridge of claim 1, wherein the release pad is linearly movablein a direction of an axis of rotation of the reel.
 5. The tape cartridgeof claim 4, wherein the brake member is movable between the lockingposition and the unlocking position in conjunction with the linearmovement of the release pad.
 6. The tape cartridge of claim 1, furthercomprising a case which rotatably accommodates the reel.
 7. The tapecartridge of claim 6, wherein the reel comprises a reel gear which isengageable with the rotating member of the tape drive for transmittingthe driving force.
 8. The tape cartridge of claim 7, wherein an apertureis formed in the case, and the reel gear is exposed through the apertureto outside the case.
 9. The tape cartridge of claim 8, wherein the reelgear and the release pad are respectively engageable, through theaperture, with the rotating member of the tape drive.
 10. A tapecartridge which is insertable at a tape drive which includes a rotatingmember and carries out at least one of reading and writing of data, thetape cartridge comprising: a reel inside the tape cartridge, therotating member of the tape drive being engageable with the reel at atime of insertion of the tape cartridge, for transmitting rotary drivingforce to the reel; a brake member which is reciprocally movable betweena locking position for prohibiting rotation of the reel and an unlockingposition for enabling rotation of the reel; and an abutting portionprovided at the brake member, the abutting portion being fabricated ofmetal and including an abutting surface which is capable of abuttingagainst the rotating member for moving the brake member to the unlockingposition at the time of insertion of the tape cartridge.
 11. The tapecartridge of claim 10, wherein the abutting surface comprises a flatsurface.
 12. The tape cartridge of claim 10, wherein the abuttingsurface comprises a protruding surface.
 13. The tape cartridge of claim10, wherein the abutting surface comprises a spherical surface with aspherical radius of at least 3 mm.
 14. The tape cartridge of claim 10,further comprising an urging member which continuously urges the brakemember toward the locking position.
 15. The tape cartridge of claim 10,further comprising a case which rotatably accommodates the reel.
 16. Thetape cartridge of claim 15, wherein the reel comprises a reel gear whichis engageable with the rotating member of the tape drive fortransmitting the driving force.
 17. The tape cartridge of claim 16,wherein an aperture is formed in the case, and the reel gear is exposedthrough the aperture to outside the case.
 18. The tape cartridge ofclaim 17, wherein the reel gear is engageable, through the aperture,with the rotating member of the tape drive.
 19. The tape cartridge ofclaim 10, wherein a through-hole is formed in the reel, and the abuttingportion of the brake member is exposed through the through-hole tooutside the case.
 20. The tape cartridge of claim 19, wherein theabutting portion of the brake member is engageable, through thethrough-hole, with the rotating member of the tape drive.